Process of supplying fuels which ignite with difficulty to internal-combustion engines.



. E. BBERLE. PROCESS OF SUPPLYING FUELS WHIGH IGNITE WITH DIPFIGULIY T0 INTERNAL COMBUSTION ENGINES.

APPLICATION FILED JUNE 17, 1913. 1,093,553.. Patented Apr. 14, 19-14 Wi /11111111111 f or c n wow;

uilill/lllmwmw UNITED sTATEs PAT EUGEN EBERLE, 0F AUGS BURG, GERMANY.

PROCESS OF SUPPLYINQ FUELS WHICHJGNITE \VITH DIFFICULTY T0 INTERNAL- COMBUSTION ENGINES.

' with difiiculty, to be advantageously used in internal combustion engines of the kind in which the air and the fuel are separately compressed, as in the well-known Diesel type' of engine. In some instances it has heretofore been necessary when using oils which burn with difiiculty in Diesel motors, such as tar oil, tar, etc., to also employ a special easily ignited fuel to start the ignition in order to insure the combustion of the heavy oil. This use of a special fuel is troublesome and complicates the valve-gear as well as increases the cost of fuel consumption.

A primary object of my invention is to overcome the necessity of employing a special easily ignited fuel when using heavy oils, the-invention being based upon the following observations and the knowledge acquired therefrom.

A constant quantity of combustion air is always drawn in and compressed in a Diesel motor independent of the load; The combustion of the fuel, injected toward the end of the stroke, increases the temperature. With diminishing load, less fuel will be injected in the cylinder during each stroke.

The smaller quantity of fuel will produce a smaller temperature increase of .the combustion air. A correspondingly smaller amount of heat will therefore be transmitted to the walls of the cylinder and the cover. On account of the lower temperature of the walls, the fresh air will be less heated during the compression in the working cylinder. As a consequence the injected fuel, during a smaller load on the machine will come in at the dead center, the influence of the lower temperature is, in the present invention, compensated for by a correspondingly earlier opening of the nozzle valve.

The quantity of the injected combustion airdepends on|the duration of opening and length of stroke of the valve'needle. In all the usual devices the fuel valve is operated by similar cams for all different loads. In .order to regulate the machine, only the necessary quantity of fuel for each stroke is changed, while the duration of opening and length of stroke of the needle valve remains constant. As a consequence, during a small load, a small quantity of fuel is injected into the cylinder with too much combustion air.

When an internal combustion engine is 7 running under normal load the combustion air is so highly heated bythe surrounding metal parts during the suction and compression strokes that the final compression temperature is so high that with the aid of the known atomizing and distributing devices even heavy oils, such as tar oil, for

example, are ignited with certainty by the compressed air. When the load decreases, however, the temperature'of the cylinder walls and the piston and the final temperature of the compressed air is lower than when the engine is running under normal load, so that certainty of ignition is impaired. If the time during which the fuel valve remains open is not varied with a decreasing load, the quantity of air entering the cylinder is excessive in proportion to the quantity of fuel injected and this excessive amount of air rapidly cools the atomizer and fuel nozzle owing to conduction of heat and vaporization of the fuel, so that certainty ofignition is still further impaired.

This excessive amount of air also blows the fuel completely out of the nozzle and, when the next charge of fuel is supplied, insuffi- Patented Apr. 14, 1914. Application filled June 17,1913. Serial No. 774,137.

cient time is given to this fuel to reach the 10 seat of the nozzle valve and completely sur round it; consequently, when the said valve is lifted, pure and comparatively cold injection air first reaches the cylinder and still further cools the not very hot compressed 0 air, so that when the fuel enters the cylinder the certainty ofignition'due to contact with this compressed air is further impaired. From this observation it follows that certain ignition of heavy fuels depends upon lifts. Further observations show that it is advantageous to allow the heavy fuel more time to vaporize under light loads than under heavy.

According to my invention I take advantage of the aforesaid observations and vary both the duration of the opening of the fuel valve and the time at which such opening occurs, relative to the turning point of the piston, viz. the upper dead center of the crank pin, in accordance with the load on the engine, while the air pressure and air supply are constant, that is to say with heavy loads the valve is opened late and remains open ,for a comparatively long period of time, while with light loads the contrary is the case. The opening of the valve therefore sometimes takes place some considerable time before the piston reaches .the position in which the crank-pin is at its upper dead center. The effect of this will be readily understood from what has already been explained. The fuel valve is preferably controlled'in the manner stated by a governor.

It has been found in practice that it is not necessary to control the time at which the valve opens and the timefdu'ring which the same is open in exact accordance with the load; it suffices generally to do this in stages. For example, one may leave the distributionunaltered from fullload to half load and then to vary it once only for the range of loads between half load and running light. If different cams are employed for this purpose one of them will serve for the range of. higher and the other for-the range of lower loads.

The accompanying drawings serve to further explain the process. I

' In these drawings: Figures 1 and 2 are elevations, partly in section, showing one form of cam mechanism for carrying out my process, and Figs. 3 and 4 are similar views showing a second form.

In Figs. 1 and 2 a device is illustrated, whereby the beginning of the early opening of the valve relative to the turning point of the piston and the duration of such opening can be varied dependently on the load, and hence on the governor. a designates the cam-shaft and b the cam having the longitudinal projection a. One of the ends (in the drawing, the left end) of the projection of this cam has a suitably curved face for raising the valve when the engine has the minimum load, and the other end a suitable face for raising the valve when the load is the maximum. As will appear more clearly from Fig. 2, the cam surfaces at each end f. The cam 32 is slid along by the governor, whereby at each particular load the corre- V sponding curved face of the cam bears against the roller (Z. Consequently the fuel valve fwillbeopened earlier in the cycle for. a light load on the engine than for a heavy one. Considering-a certain point in the cycle, for instance the upper dead center of the crank pin or the turning point of the piston, more oil will have been injected and heated at that particular point, when the engine is running light, than when it runs with full load.

The constructio-n'of the nozzle as illustrated in Fig. 2 and the following descrip-' tion thereof, forming no part of this inven tion, is merely introduced for the purpose of making the operation of the device clearer.

The fuel valvej has its seat at s where the nozzle r receiving fuel and compressed air through separate conduits, is closed toward the compression chamber of the cylinder. In the nozzle are provided several disks Z, m, n, p, q with fine holes drilled in such positions, that the holes in the individual plates do not lie opposite each other. The quantity 'of fuel necessary for each working stroke is supplied through a fuel passage K, which v opens intothe nozzle chamber above the so-called atomizing disks Z, m, n, 70, q. The fuel runs'partly through the perforated disks and is distributed over the surface of these disks. The compressed air enters the nozzle chamber r above the fuel passage. At the instant whenthe fuel mixture has to be injected into the cylinder,

the valve f opens, and the higher pressure that the air, stored in the nozzle chamber 7', possesses over the pressure in the compression chamber of the cylinder, driveswith great violence thefuel, which ispartly adhering ,to the atomizing disks and partly situated above the uppermost atomizing disk Z, through the perforations in the atomizing disks, and causes thereby an intimate intermingling of the air with the fuel This mixture of fuel and air is then driven through the fine opening 0 in the spraying disk y, when it attains very high velocity. When emitted from this opening in the large cylinder chamber, the comparatively large fuel drops in' the -mixture are torn apart into very fine particles, so that a still 'ingof a single valve. f.- Should the valve f as is the case in earlier constructions, stay open too long with a-light'load, admitting an excessively large quantity of air into the cylinder, the air will then sweep away all the fuel from the atomizing disks, and blow it into the cylinder. But if only so much air flows into the cylinder, as would be'ne 7 -essary for combustion at light load, a sma 1 quantity of fuel, so called ignition drops, will then remain close over the valve seat, during the injection of the fuel into the cylinder, as has been indicated by the black spots 6. in Fig. 2. During the subsequent opening of the valve 1, this small quantity of fuel, ignition drops, enters the cylinder in advance and starts .the combustion therein. If these ignition drops are not formed, on account of the passing in of too great a quantity of air, as has been described above, cold air will then first enter the eylinder from the space 1*, when the valve is opened the next time, and causes the unfavorable action for the combustion.

'In Figs. 3 and 4 a device is illustrated wherein cam faces 1, 2, 3, 4, adapted only for certain loads, 6. g. for four loads, are moved into action successively, and hence, in stages. In order that the cam 71 may be easily slid along the shaft (1 the various cam faces are connected one to another by slanting guide faces 9, h, 2', so that when the cam is axially shifted, the roller d slides on a guide face up or down tQthe next higher or lower cam face. In this case the cam can beshifted very readily by hand.

Similarly to Fig. 2, Fig. 4 clearly indicates the distributions of the d surfaces. Considering for instance the vertical center line in the figure 'as coinciding with the upper dead center of the crank delayed.

ifferent cam pin, itis evident that with cam surface 1 inaction, almost all the fuel for the stroke has been admitted and had time to be heated before the dead center point is reached; whereas the valve is just starting to open when cam surface 4 is in action.

1. The process of supplying to internal combustion engines of Diesel type, mixtures containing fuels which ignite with difliculty and varying the fuel element according to the load upon the engine, which consists in delaying the commencement of fuel introduction relatively to the dead center of the engine, proportionately to the increase of load, and increasing the duration of admission as the period of introduction is delayed.

. 2. The process of supplying to internal combustion engines of Diesel type, mixtures containing fuels which ignite with difficulty and varying the fuelelement according to the load upon the engine, which consists in delaying'the commencement of fuel introduction relatively to the dead center of the engine, proportionately to the increase of load, and increasing the quantity of fuel supplied as the period of introduction is 3. The process of supplying to internal combustion engines of Diesel type, mixture containing fuels which ignite with difiiculty and varying the fuel element according to the load upon the engine while maintaining the air supply at constant pressure, which consists in delaying the commencement of fuel introduction relatively to the dead center of the engine proportionately to the in crease of'load, and increasing the duration of admission as the period of introduction is delayed.

In testimony whereof, I aflix my signature in the presence of two witnesses.

EUGEN EBERLE.

. Witnesses.

HANSON O. Come, EUGiaNn M. BoNeii. 

